Field of the Invention
Embodiments relate to a touch sensor.
Discussion of the Related Art
An input signal of a touch sensor may include a driving signal received via capacitance between the driving and sensing electrodes of a touch panel and a noise signal received via capacitance between an object (e.g., a finger) touching the touch panel and the sensing node of the touch panel. The sensed signal may be an overlap signal of the two signals.
When electromagnetic noise radiated by a fluorescent lamp located near a touch sensor is severe, or when a charger directly connected to a touch sensor causes or injects strong noise, the output of an amplifier (e.g., an operational amplifier) in an analog signal sensing unit of the touch sensor may deviate from a normal operational range. Thus, the output waveform of the analog signal sensing unit may be distorted, and touch information may be delivered abnormally.
The output signal of the amplifier in the analog sensing unit may be prevented from deviating from the normal operational range by increasing the capacitance of a feedback capacitor in the analog sensing unit, or by using a high-order analog filter. However, in this case, the circuit area may increase, and additional power may be consumed.